The present invention is directed to hydrocarbyl fuel compositions having improved low temperature characteristics. More particularly, it is directed to such compositions having a major amount of a suitable distillate fuel and a minor effective amount of an additive compound consisting of the reaction product of an ester derivative of a branched-chain monocarboxylic acid having at least one tertiary-amine group, an epoxide and a carboxylic acid and to said additive compounds.
It is well known that distillate fuels such as diesel fuels are subject to poor flowability at low temperatures and have relatively high cold filter plugging points. Many expedients have been attempted in the prior art to overcome these adverse cold temperature properties.
U.S. Pat. No. 4,108,613 teaches the use of a mixture of (1) the reaction product of an epoxidized alpha-olefin with a nitrogen-containing compound selected from ammonia, an amine, a polyamine or a hydroxyamine and (2) an ethylene-olefin copolymer as an additive to depress the pour point of hydrocarbonaceous fuels and oils.
U.S. Pat. No. 3,962,104 discloses lubricating oil compositions containing minor amounts of quaternary ammonium salts useful as an oil improving additives. The quaternary ammonium salts utilize a cation derived from the reaction product of one molar proportion of a tertiary amine with one or more molar proportions of an olefin oxide and an amount of water in excess of stoichiometric. The anion is derived from an organic acid and the tertiary amine has substitutents which are alkyl, alkenyl, substituted alkyl, substituted alkenyl, aromatic or substituted aromatic groups.
U.S. Pat. No. 4,491,455 describes C.sub.12 -C.sub.30 linear fatty acid esters of hydroxyamines useful as a means of improving the cold flow characteristics of hydrocarbon fuel oils.
None of these prior art materials utilize the specific branched chain acid reaction products as described below or provide a breakthrough in cold flow plugging point and pour point depression of distillate fuels to ensure the desired performance at low temperatures. Additionally, the materials in accordance with the invention are applicable to a wide variety of distillate (diesel) fuels whereas presently commercially available additive materials are more specific and generally work for only one or two particular fuels, not over a broad range of available fuels.